Focus Fanatics Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I am new here and I hope I am posting this correctly. I have a 2003 ford focus se. I am getting a code of p0171 which is a misfire. I replaced spark plugs, wires, cleaned map sensor, replaced front o2 sensor, had a hose off from egr valve at elbow was slightly caved in replaced. I had computer reset so light is off. However once in a while when I am driving between 52-60 mph I get a bucking one time and stops. It does not happen all the time. Could this have anything to do with the misfire or is it something to do with AT? The engine light of course is not back on because it needs to reset itself. I am replacing the fuel filter today. Any ideas on the bucking?[scratch]
 

·
has a screw loose
Joined
·
9,927 Posts
Have you checked your Throttle Position Sensor and Idle Air Control Valve ?


I just looked your code up and here is what I found :


P0171 - System to Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit. For lean and rich DTCs:
Fuel system
Excessive fuel pressure.
Leaking/contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Vapor recovery system.
Induction system:
Air leaks after the MAF.
Vacuum Leaks.
PCV system.
Improperly seated engine oil dipstick.
EGR system:
Leaking gasket.
Stuck EGR valve.
Leaking diaphragm or EVR.
Base Engine:
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.
A SHRTFT-1,2 PID value between -25% to +35% and a LONGFT-1,2 PID value between -35% to +35% is acceptable. Reading beyond these values indicate a failure.
 

·
Registered
Joined
·
16,194 Posts
I just had something like this on my mom's mercury tracer which is a ford escort. Her TPS sensor was at fault. I replaced a lot of things before this sensor and it hasnt acted up since
 

·
has a screw loose
Joined
·
9,927 Posts
I just had something like this on my mom's mercury tracer which is a ford escort. Her TPS sensor was at fault. I replaced a lot of things before this sensor and it hasnt acted up since

I just did the same thing on my 94 F 150 , about 55 mph the thing would start bucking then clear up when I took my foot off the gas but got back up to around the same speed again it would start all over again.
 
1 - 5 of 5 Posts
Top